First, think about WHY you want to increase the size of the video RAM.
Do you want to have more pixels (X times Y dots on screen)?
Do you want more colors (32 bit vs 16 bit for example)?
Do you want more/better 3D graphics?
Do you want faster game performance?
Etc?
More video RAM probably will help the first two directly.
But, more video RAM may not necessarily help the second two, since they also
depend on other things, such as whether the video sub-processor on the
motherboard supports Direct X and which version.
Game speed also depends on the type/quality/speed of the PC's RAM as well as
video RAM. (Of course, in your case these are the same.) Thus, designating
more of the current speed RAM to video may not help. That said, 8 Meg seems
very low for video RAM on a modern PC. That is more like a Windows 98
vintage value, and so I can see where you might want designate 32 to 64 Meg
for video.
Note that Game speed can also be a function of CD drive speed, if played
from a CD, or hard drive speed, if installed on the hard drive. One way to
improve CD drive speed is to install a virtual CD drive, in addition to the
physical one you already have. You may need to uninstall and re-install the
game via the virtual drive, since some games play only on the drive from
which they were originally installed. See for example:
http://www.magiciso.com/tutorials/miso-magicdisc-overview.htm
If the PC is fairly old, you might have a low-speed hard drive, possibly
ATA/33. That can be upgraded to ATA/100, but you will still get only ATA/33
performance, if the motherboard's disk controller is ATA/33. If the PC is a
desktop, you could get around that sort of motherboard limitation by
installing a PCI-to-ATA/100 card, which is fairly cheap. In conjunction
with an ATA/100 hard drive you would see a noticeable increase in disk
speed. I did this once on an old Gateway and it essentially doubled my read
and write speed.
If the PC is a desktop, installing a separate video card, with its own RAM
and intrinsic support for recent versions of DirectX, might be a good
investment. But, first check whether the PC has a BIOS option to use a
video card instead of its intrinsic video. (Most do.) Next, determine the
type of video card it can accept. For example, it is PCI, AGP, or PCI-X?
If AGP, is it 5 volt, 1.5 volt, or 0.8 volt. In most cases the wrong card
will not fit in the expansion slot. But, in the case of AGP, two of the
three flavors might fit, but only one might work. Worse, it is possible
that the wrong voltage card could harm the motherboard, although many
motherboards test for compatibility, and refuse to run, providing instead a
beep code.
Finally, and this is a difficult thing to accept, sometimes it is a better
investment to get new, modern, low-end PC than to invest in upgrades to your
current PC. Today's bottom-line PC can out perform a top-of-the-line model
form a few years ago. For example, a Dell can be gotten with a 128 Meg
video card, 1Gig of plain RAM, 250 Gig hard drive, DVD writer drive, etc for
about $400. (That is without a monitor.) Check the web and physical
stores for other options, before spending too much on any upgrade.
